What to do next

First of all my use of Cubase 6 Elements LE or Al (whatever the confusing suffixes mean, that’s not the point I want to raise .)
Over the years learning the working product has been fine after the initial problems getting it up and running.
Now as always the iMac in which it was installed is dead, not resting,DEAD. Now along comes the same old problems with installing and compatibility,the same problems of technology racing ahead and not getting on with each other unless at the cost to the customer.

I have the original install disk but my replacement machine has no usable disk drive

Question: My Cubase is Al 6 (according to the disk) advice is needed on what I should do either upgrading my operating system OR Cubase.
Thanks for any advice.

You can download Cubase AI 6 from your MySteinberg, if you registered it like you were told to by the program and the documentation.

After downloading it, use the Steinberg Installation Helper. Follow the instructions:
https://www.steinberg.net/index.php?id=content_and_accessories_sait&L=1

You can upgrade from your Cubase AI 6 to Cubase Elements 9.5 for less than 50 bucks. It has better support for modern operating systems and superior CPU and graphics performance, on top of offering faster workflow and a ton of new content and features that weren’t in Cubase AI 6. It’s a huge upgrade.

I will look into that https://www.steinberg.net/en/shop/buy_product/product/cubase-elements-95.html
Graphics performance sounds interesting in 9.5, Macs tend to die of that in droves.
Thanks for advice Tp